Intravascular ultrasound (IVUS) catheters and methods for imaging are known. For example, U.S. Pat. No. 5,000,185 to Yock, the entire disclosure of which is incorporated by reference, discloses devices and methods for high-resolution intravascular ultrasound imaging to assist with the administration of vascular interventional therapy and to monitor the results of such therapy. In Yock, an ultrasonic transducer is carried by the distal end of a catheter adapted for insertion into a blood vessel, whereupon either the transducer or another element, such as an ultrasound mirror, is rotated and/or translated relative to the catheter to image different portions of the vessel.
In spite of advances in the art, however, there continues to be a need for a catheter apparatus that can provide longitudinal scans of a vessel surface along the axis of the vessel, and oblique scans which examine vessel regions distal of the catheter tip, without the need for an accompanying longitudinal movement of the transducer or other catheter element along vessel axis.